Bacteriophages are bacterial viruses that attach to their specific hosts and kill them by internal replication and bacterial lysis involving a complex lytic cycle involving several structural and regulatory genes. Phages are very specific in that they only attack their targeted bacterial hosts. They cannot infect human or other eukaryotic cells. Bacteriophages were first identified, in the early part of the 20th century by Frederick Twort and Felix D'Herelle who called them bacteriophages or bacteria-eaters (from the Greek phago meaning to eat or devour) (Duckworth, D. H. (1976). Who discovered bacteriophage? Bacteriol Rev 40(4): 793-802; Summers, W. C. (1999). Bacteriophage discovered. Felix d'Herelle and the origins of molecular biology. New Haven, Conn., Yale University Press: 47-59). At that time, with the age of antibiotics still in the future, bacteriophages were considered to be a potentially powerful cure for bacterial infections, and they were therapeutically utilized throughout the world during the pre-antibiotic era. The use of phages in humans was found to he very safe; however, phage therapy did not always work and, with the advent of antibiotics that were effective against a broad spectrum of pathogenic bacteria, it gradually fell out of favor in the United States and Western Europe. Several factors (reviewed in more detail in Sulakvelidze, A., Z., Alavidze, et al. (2001). Bacteriophage therapy. Antimicrob Agents Chemother 45(3): 649-659; Summers, W. C. (2001). Bacteriophage therapy. Ann Rev Microbiol 55: 437-51), including the lack of a broad understanding of phage biology and inadequate diagnostic bacteriology techniques, contributed to the failure of some of the early phage therapy studies and to the associated decline of interest in phage therapy in the West. At the same time, phage therapy continued to be utilized in the former Soviet Union and Eastern Europe, where phage therapy still is being used to treat a wide range of bacterial diseases ranging from intestinal infections to septicemia. Comprehensive information about human and veterinary applications of bacteriophages has been recently reviewed by several investigators (Alisky, J., K. Iczkowski, et al. (1998). Bacteriophages show promise as antimicrobial agents. J Infect 36(1): 5-15; Summers, W. C. (2001). Bacteriophage therapy. Annu Rev Microbiol 55: 437-51; Merril, C. R., D. Scholl, et al. (2003). “The prospect for bacteriophage therapy in Western medicine.” Nat. Rev Drug Discov 2(6): 489-497; Sulakvelidze, A. and P. Barrow (2005). Phage therapy in animals and agribusiness. Bacteriophages: Biology and Applications. E. Kutter and A. Sulakvelidze. Boca Raton, Fla., CRC Press: 335-380; Sulakvelidze, A. and E. Kutter (2005). Bacteriophage therapy in humans. Bacteriophages: Biology and Application. E. Kutter and A. Sulakvelidze, Boca Raton, Fla., CRC Press: 381-436).
Methicillin-resistant Staphylococcus aureus (MRSA) is a type of Staphylococcus aureus that is resistant to certain antibiotics, in particular methicillin. MRSA may also be resistant to other antibiotics including but not limited to oxacillin, penicillin, and amoxicillin. Some MRSA strains may also be resistant to vancomycin. Staphylococcal infections, including MRSA, occur most frequently among persons in hospitals and healthcare facilities (such as nursing homes and dialysis centers) who have weakened immune systems. MRSA infections that occur in otherwise healthy people who have not been recently (within the past year) hospitalized or had a medical procedure (such as dialysis, surgery, catheters) are known as community-associated (CA)-MRSA infections. MRSA is important because of its pathogenicity, limited treatment options, and MRSA are transmissible. “Healthcare-Associated Methicillin Resistant Staphylococcus aureus (HA-MRSA)” from the Centers for Disease Control website (2008).
MRSA is also used to describe multidrug-resistant S. aureus (MDRSA) strain, which is used to refer to a Staphylococcus aureus strain that is resistant to at least oxacillin, lincosamides, erythromycin, and chloramphenicol.
Despite the use of bacteriophage in various practical settings, including the treatment of diseases in various animals, there remains in the art a need for the discovery of novel bacteriophages, selection of optimal bacteriophages for specific practical applications, and identifying methods for using these bacteriophages in several critical areas, including clinical applications, food safety-related uses and environmental decontamination. For example, one significant need concerns the treatment of processed or unprocessed food products to reduce, eliminate or prevent colonization with undesirable bacteria such as pathogens responsible for food-borne illness and food spoilage organisms. A second critical area of need concerns the removal of undesirable bacteria from industrial environments such as food processing facilities to prevent colonization thereof. A third critical area of need concerns the removal of antibiotic resistant organisms from environments where they may be passed to susceptible humans and animals, such as hospitals, nursing homes, veterinary facilities, and other such environments. A fourth critical area of need is in the reduction or elimination of colonization of patients, healthcare workers, and other individuals by antibiotic-resistant pathogens, specifically including methicillin-resistant Staphylococcus aureus (MRSA) as well as MRSA strains that are also resistant to vancomycin. Additionally, new bacteriophage and methods of using the same are needed for the prevention or treatment of animal and human bacterial disease, particularly those diseases caused by antibiotic-resistant organisms.